RegisteredListener: use try...finally to stop timings

While event handlers should not throw exceptions, we need to make sure the timings get stopped in the correct order, because the parent Event timer will be stopped due to using a finally block.
If this happens while the handler timing is still running, a second exception will occur, obscuring the real error.

src/event/RegisteredListener.php

@@ -57,8 +57,11 @@ class RegisteredListener{
 			return;
 		}
 		$this->timings->startTiming();
-		($this->handler)($event);
-		$this->timings->stopTiming();
+		try{
+			($this->handler)($event);
+		}finally{
+			$this->timings->stopTiming();
+		}
 	}
 
 	public function isHandlingCancelled() : bool{